Long-term cause it has at this point been around for actual decades.

If you’re gonna use an overlay network like Tailscale I would highly recommend also taking a look at netbird. Similar concept, but fully self hostable if the need arises (but not recommended unless you have a specific need).

My various servers, firewall and nas are relatively power optimized. Everything including switches (most with some 10g ports) and access points is 160 W or so. I can’t give you monthly usage, as I’ve got solar+battery so it’s frequently just 0 kWh for some days. It’s also rather hard to separate from the other power usage in the house when solar doesn’t fit cover it.